If you can only carry one tool for personal defense/burglary, make it the Ka-Bar Becker TacTool ($140). The result of a collaboration between John Benner of the Tactical Defense Institute and Ethan Becker of Becker Knife and Tool, the TacTool offers a 7.75-inch blade, and works for prying open doors or windows, cutting, bashing out windows, lifting nails and hinge pins, and more.